It is well known to those skilled in the art that aromatic hydrocarbons are a class of very important industrial chemicals which find a variety of uses in petrochemical industry. It is also well known to those skilled in the art that catalytically cracking gasoline-range hydrocarbons produces aromatic hydrocarbons such as, for example, benzene, toluene, and xylenes (hereinafter collectively referred to as BTX) in the presence of catalysts which contain a zeolite. The product of this catalytic cracking process contains a multitude of hydrocarbons including unconverted C.sub.5 + alkanes, C.sub.5 + alkenes, C.sub.5 + cycloalkanes, or combinations of two or more thereof; lower alkanes such as methane, ethane, and propane; lower alkenes such as ethylene and propylene; and C.sub.9 + aromatic compounds. Recent efforts to convert gasoline to more valuable petrochemical products have therefore focused on improving the conversion of gasoline to more valuable aromatic hydrocarbons in the presence of zeolite catalysts. For example, a gallium-promoted zeolite ZSM-5 has been used in the so-called Cyclar Process to convert a hydrocarbon to BTX. The aromatic hydrocarbons can be useful feedstocks for producing various organic compounds and polymers. However, heavier, less useful aromatic compounds having 9 or more carbon atoms per molecule (hereinafter collectively referred to as C.sub.9 + aromatic compounds) are also produced by the conversion process. Furthermore, a zeolite catalyst is generally deactivated in a rather short period because of depositions of carbonaceous material, generally coke, on the surface of the catalyst.
Accordingly, there is an ever-increasing need to develop a catalyst and a process for converting these heavier and less useful aromatic compounds to the more valuable BTX hydrocarbons (hereinafter referred to as hydrodealkylation process) and, in the meantime, for suppressing the coke formation. Such development would also be a significant contribution to the art and to the economy.